When you are assembling an RF network cable telecom test bench, the first decision is not which brand is better but which measurement gap you need to close. The HP Hewlett Packard 85020A Directional Bridge and the TOJOIN RF SHIELD BOX MS3020-A are both used RF test instruments in the $500 to $749.99 range, yet they perform different jobs. The HP covers RF measurements and signal testing from 10 MHz to 4.3 GHz. The TOJOIN is built around isolating a device from outside RF energy. Pick the one that matches the test procedure you run most often.
Quick verdict
Buy the HP 85020A when your work involves signal testing, microwave measurements, and general RF measurements along a cable-connected path. It comes with an attached cable and a carry/storage case. Buy the TOJOIN MS3020-A when you need radio frequency shielding and protection around a device under test. The price gap is meaningful, but the larger difference is the job each tool performs.
At a glance
| Product | Price | Type | Condition |
| HP Hewlett Packard 85020A Directional Bridge 10MHz-4.3GHz | $500.00 | Directional Bridge | Used |
| TOJOIN RF SHIELD BOX MS3020-A | $749.99 | Radio Frequency Shielding Box | Used |
Where each wins
The HP 85020A wins for cable and signal-path work. Its directional bridge design supports RF measurements and signal testing across 10 MHz to 4.3 GHz. The attached cable and carry/storage case come with it, provided you address the aged foam inside the case.
The TOJOIN MS3020-A wins for controlled-environment testing. If your radio frequency equipment needs protection from ambient signals, the TOJOIN shielding box creates that separation. It is a single unit, so the hardware you need is the box itself.
HP Hewlett Packard 85020A Directional Bridge
The HP 85020A is a used directional bridge covering 10 MHz to 4.3 GHz, and it is priced at $500.00. The package includes the directional bridge unit, an attached cable, and a carry/storage case, which is useful for keeping the instrument together on a workbench or in transport. The case foam has deteriorated with age and may need replacement or cleaning before the case is usable. The unit is sold as-is, so plan to account for that condition. Choose the HP when your priority is RF signal and microwave measurements that require a directional bridge with a wide frequency range. Its main limitation is the physical condition of the case foam and the as-is sale terms.
TOJOIN RF SHIELD BOX MS3020-A
The TOJOIN RF SHIELD BOX MS3020-A is a used radio frequency shielding box priced at $749.99. It is designed to provide RF shielding and protection during testing, which helps support accurate and reliable results when you measure radio frequency equipment. The model number is MS3020-A, and the unit quantity is one, so you work with a single enclosure rather than a set of parts. The TOJOIN box is the right choice when your test procedure needs to keep outside signals away from the device under test. Its main limitation is the higher price compared with the directional bridge in this comparison; you are paying for a different RF test function.
Final choice by use case
Choose the HP 85020A if you need to make RF signal and microwave measurements across 10 MHz to 4.3 GHz and you are comfortable doing a little cleanup on the case. Choose the TOJOIN MS3020-A if your radio frequency equipment testing depends on shielding the device from interference. The $249.99 difference between the two matters if budget is tight, but it should not override the basic question: do you need to measure signals in a cable path, or contain signals around a device? Let the measurement problem decide.
